Video may consist of a series of images shown in rapid succession. Each image may represent a frame. Some systems, such as traditional television systems, may divide each image into a series of scan lines. Some conventional analog and digital television systems arrange the scan lines of each frame into two consecutive fields, one containing all even lines, and one containing the odd lines. The fields are displayed in succession at twice the rate of the nominal frame rate.
In video generated by traditional television and video cameras, the two fields of a frame may be taken at slightly different times, which results in an effectively doubled time resolution as compared with non-interlaced video, improving the viewer's motion perception.
These benefits can only be experienced if the display shows the individual fields in the same order in which they were shot. Generally, only traditional cathode ray tube (CRT)-based televisions and monitors may be capable of doing so. If correctly adjusted, they may not suffer from interlacing artifacts. But when the fields of the original footage are displayed in a different order from the order in which they were shot (i.e. when two fields taken at different points in time are re-combined to one frame), visual defects, such as interlace artifacts or combing, may occur with moving objects in the image.
Display technology has evolved from cathode ray tubes that generate images using interlaced scans, to flat digital display devices that generate images using progressive scan. To handle interlace artifacts, liquid crystal display (LCD) and plasma consumer television sets and monitors may include circuitry and/or software that converts interlaced video into progressive video. The process of converting interlaced video into progressive video is called de-interlacing.
Deinterlacing, if done poorly, can introduce image degradation. Conventional deinterlacing algorithms may be divided by two categories: intra-field processing and inter-field processing. Intra-field processing may use a relatively simple algorithm; however, such an algorithm cannot overcome the loss of vertical resolution. An algorithm in the category of inter-filed algorithms is the weave, which may result in noticeable artifacts, especially around moving areas. Other inter-field algorithms, such as motion adaptive (MA) and motion compensation (MC) algorithms may yield better results than the intra-field algorithms, but do not always provide optimal results.